Suction device for medical purposes

ABSTRACT

The invention relates to a suction device for medical purposes with one or more side apertures and with a valve which responds to a vacuum. The invention is characterised in that the side apertures are covered by film halves which overlap in the middle, one of said halves being made from highly elastic thin material while the other is made from a stiff inflexible material and covers the flexible film in the overlap region. The side apertures can also take the form of elongated apertures. An advantage of this embodiment is the low damage to tissue when used in the overpressure area especially in minimally invasive surgical applications.

This application is the national phase of international applicationPCT/EP96/05488 filed Dec. 7, 1996 which designated the U.S.

The invention relates to a suction device for medical purposesparticularly suitable for usage in Minimal Invasive Surgery (MIS).

In surgery, extravasating blood, tissue liquids, tissue fragments, bonefragments and -dust as well as pus, but also rinsing liquid such assodium chloride solution or Ringer solution have to be removed from theregion under treatment. While in the past mull swabs were used, thesedays suction devices are engaged. In dentistry e.g., salvia, blood, andleft-overs from drilling have to be succed off. In intensive surgery,anesthesia, and endoscopic examination, body liquids of a variety ofviscosities and consistencies have to be succed off (e.g., mucus, blood,urine, stool, bile, gastric juice, etc., also contrast liquids).

In general, suction devices for medical purposes consist of apermanently installed or a mobile vacuum pump, which is connected to alow pressure collecting containe that in turn, via an over-flowprevention apparatus, is connected to a so-called secretion bottle whichin turn is connected to the suction tip via a suction tube. Both smallvolume and large volume suction apparatus exist, where such devices aredenoted large volume suction apparatus whose inner diameter is largerthan 4.9 mm. These suction apparatus can be plastic, but they can alsobe made from metal, or from other material.

When, while sucking off, tissue completely covers the aperture of thesuction tip of the suction apparatus, low pressure is established, whichcan touch on the order of the pump's low pressure of 0.1 bar. Thus,tissue is pressed into the sucking aperture by the air pressure so thattraumatic damage can be inflicted onto the tissue. In addition, tissuecan be vered off at the inner edge of the sucking aperture, whichlikewise can lead to injuries.

Suction devices for medical purposes are known already. The DE-PS 40 04373 describes suction devices for medical purposes consisting of asuction aparatus made from metal or plastics, which is equipped with oneor several side apertures with a low pressure valve. According to thepatent, the side apertures are shaped as elongated holes or ascontinuous grooves and they are covered with thin slitted film orslittable film respectively which can either be mounted as a tube orwhich can be pasted as film strips. In this way it can be avoided, evenat a low pumping pressure, close to 0.1 bar, that the suction tip sucksfast to the tissue. So-called traumatic tissue defects do not occur anymore. Moreover, optimal adaptation of the sucking power to theindividual circumstances can be achieved by varying the slit size. Thus,at the same time, vacuum control in the way of manual, temporarycoverage of the side apertures at the suction tip, considered disturbingduring surgery, is rendered superfluous. As opposed to suction apparatuswhich are equipped in a common way, with side apertures above thesuction tip, suction devices according to DE 40 02 373 can be operatedwithout disturbing noise.

Although suction devices known according to the state of the art,meanwhile, largely help to avoid to traumatic tissue injuries as well asdisturbing operating noises, and, in particular, are successfully usedin neuro surgery, their range of service is constructionally limited tosuch operations that take place at atmospheric pressure. However, it canbe observed that the number of operations, frequently conducted at highpressure of 0.01 to 0.1 bar (above atmospheric pressure), such as e.g.in the field of minimal invasive surgery, is steadily increasing. Due torapid progress of medical technology as well as of opto electronicsMinimal Invasive Surgery gathers importance. Concerning MIS, the healingprocess can be accelerated and the duration of the usually costintensive stationary treatment can be reduced considerably since both,the operation expenditure can be kept at low levels, and the actualsurgical treatment can be reduced to a minimum. In particular, given thesocio-political importance of cost-reducing measures in the health-caresystem, the reduction of the stationary treatment's duration is likelyto foster MIS operation techniques and applications.

Minimal Invasive Surgery, as well, requires the removal of blood andrinsing liquid by a suction device during surgical treatment. In orderto avoid traumatic injuries of tissue as a consequence of the suctiontip's sucking fast, the advantageous features of a suction deviceaccording to DE 40 02 373 should not be relinquished in Minimal InvasiveSurgery. MIS treatment is generally conducted at high pressure of 0.01to 0.1 bar. Since the side apertures of the suction device, in order tofunction according to the patent, are positioned outside the body i.e.,in a region of normal pressure, one would risk the loss of pressure gas,in the case of the slitted film according to DE 40 02 373, whenever thesuction device is not operating.

Hence, there is yet demand for suction devices that can be used also towork at high pressure and which in this case, in particular, can be usedin MIS treatment, while not simultaneously giving rise to traumaticinjuries of tissue and to undesired background noise, and which, inaddition, are of simple design and, when necessary, are easily cleanedand sterilized. Scope of the invention is therefore to maintain theadvantages of DE 40 02 373 in the case of operations conducted at highpressure, and in particular in the case of such operations asMinimal-Invasive-Surgery.

According to the invention, suction devices with one suction aparatusmade of plastics or metal are now proposed which are equipped with oneor several side apertures with a low pressure valve and which arecharacterized in that the side apertures are covered by concentricallyoverlapping film halves of which one consists of highly elastic thinmaterial while the other is made from rigid inflexible material. Theelasticity of both materials is important whereas the strength of thefilms is not of major importance. For this reason equally strong filmsmay be used. Furthermore, crucial with regards to the invention is thatthe rigid film covers the flexible film in the overlap region. It isadvantegous if the film strips each cover more than half of the aperturefrom the opposite sides respectively. The rectilinear film strips can beaffixed to the surface of the suction tip such that the overlappingedges of the film run parallel to each other and the overlap region, inthe case of elongated holes, runs along the middle axis.

The side apertures can be shaped as elongated holes and usually they arepositioned at a large distance to the suction tip. Thus, the valvessurely can stay outside the body i.e., in the region of normal pressurewhile the suction tip is immersed into the high pressure region.

In this way, critically low pressure leading to traumatic tissueinjuries is surely avoided. At the same time the closure of the suctiontube is assured by pressing the flexible film strip against theinelastic film strip when high pressure builds up inside the suctiontube. Any leakage of pressure gas does not occur. Hence, steadyoperation conditions are ensured and the suction aparatus can remaincontinuously inside the operation region. The suction tip, from theoutside, neither needs to be moved to nor removed from the operationregion according to the needs and necessities.

A discription of the invention using the drawings is given below:

FIG. 1 shows a side view of a suction aparatus according to theinvention.

FIG. 2 shows a cross-sectional view of the same suction aparatus wherehigh pressure is applied inside the suction tube.

FIG. 3 shows a cross-sectional view of the same suction aparatus where apressure is applied inside the suction tube which is less than acritical low pressure.

FIG. 4 shows an elongated hole covered with foil strips seen from above.

The suction aparatus (1) is equipped with an aperture (2) and one orseveral elongated holes (3) which in turn are covered by filmsoverlapping in the middle where one of the films (5) is made fromflexible material, while the other (6) is made from rigid material. Thefilms (5, 6) are arranged in such a fashion that in the overlap regionthe rigid film (6) covers the flexible film (5). Seen from above (FIG.4) it becomes obvious that the overlapping film edges (7) and (8) runparallel to the longitudinal axis of the elongated hole, the film edgeseach cover slightly more than between one half and up to approximately2/3 of the surface of the elongated hole and that the overlap region ispositioned approximately in the region of the longitudinal axis of theelongated hole. The utilized films advantageously consist of flexible orrigid plastic film materials respectively and can easily be affixed tothe suction tube.

We claim:
 1. Suction device for medical purposes, suitable to be used inMicro-Invasive-Surgery (MIS), with at least one suction opening as wellas one or several side apertures where the side apertures are eachequipped with a low pressure valve, characterized in that the sideapertures are covered with film halves which overlap in the middle whereone of said film halves consists of highly elastic thin material and theother consists of rigid inflexible material where the rigid film coversthe flexible film in the overlap region.
 2. The suction device accordingto claim 1, wherein the side apertures are shaped as elongated holes. 3.The suction device according to claim 1, wherein the side apertures arelocated in a region of normal pressure.
 4. The suction device accordingto claim 1, wherein the flexible and the rigid films each cover morethan half of the hole's surface from the opposite sides respectively. 5.The suction device according to claim 1, wherein the overlapping filmedges run parallel to each other.
 6. The suction device according toclaim 1, wherein the films are plastics.